So yesterday I was super happy to finally have an ultrasound and see a healthy baby that is growing appropriately. The dr showed us the fetal pole and yolk sac and said it was measuring exactly 6w4d. She also said she may see a little flicker to the left. She scheduled us to come back 9 days later at 8weeks. I didn't question anything until I got home and read a lot of other people who saw and heard a heartbeat and knew he Heart rate at the same gestational age I am. Then I started worrying that something wasn't right. Does this sound like something I should worry about?